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Technical white paper | HP Enterprise Virtual Array Storage and VMware vSphere 4.x and 5.x configuration best practices
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Figure C-2. I/O routes
In this example, even though the EVA array has a total of eight controller ports (four on each controller), all I/O seems to be
routed through just two ports on Controller 1. Note that SAN zoning is only allowing each HBA to see ports 1 and 2 of each
controller, explaining why no I/O is seen on ports 3 and 4 even though round robin I/O path policy is being used.
The system is unbalanced because, despite having three Vdisks preferred to Controller 2, most of the workload is handled
by Controller 1.
You can verify this imbalance by reviewing the appropriate Vdisk path information. Figure C-3 provides path information for
Vdisk9; Figure C-4 provides information for Vdisk5.
Figure C-3. Path information for Vdisk9
Figure C-4. Path information for Vdisk5